The present invention relates to a method and system for efficiently manufacturing semiconductor, electric or electronic devices or the like with high reliability and an inspection method and system for inspecting the semiconductor devices.
A conventional manufacturing process control system controls a manufacturing process on the basis of data obtained through the automatic inspection and repair of products. When the manufacturing process control system inspects products by an automatic inspecting system, the parameters of defect identifying standards to be used by the automatic inspection system are changed properly to enhance the reliability of inspection when the automatic inspection system provides excessively large amount of false information regarding nondefective products as defective or when residual defect ratio is excessively large.
A product inspected by the automatic inspection system and proved to be nondefective is sent to the next process, and repairable defective products are sent to a repairing process and are sent to the next process after being repaired. The operator monitors the condition of the manufacture of products statistically and, when necessary, changes the parameters for controlling the condition of the manufacturing machines to regulate the condition of the manufacturing process.
More concretely, in a semiconductor manufacturing process, presumably defective products found by using a visual inspection instrument, such as disclosed in Japanese Patent Laid-open (Kokai) No. 61-151410 or No. 62-43505, or a foreign matter inspection instrument, such as disclosed in Japanese Patent Laid-open (Kokai) No. 54-101390, for specifying presumably defective products are examined visually by means of a microscope included in the inspection instrument or a separate microscope to classify defects including foreign matters and defective patterns, and false information. A method of classifying detected defects using a multifocus image is disclosed in Japanese Patent Laid-open (Kokai) No. 2-170279.
Recently, Galai Laboratory of Israel and ADE Co. of the U.S.A. published cooperatively an automatic classification technique (M. Luria, E. Adin, M. Moran, D. Yaffe and J. Kawaski, xe2x80x9cAutomatic Defect Classification Using Fuzzy Logicxe2x80x9d, ASMC ""93 Boston Mass., 1993), the details of which is unknown. Results of classification of defects are analyzed, manufacturing machines presumably causative of defects are specified on the basis of the results of analysis and results of inspection carried out in other processes. Skilled members of the staff of the manufacturing process relevant to the specified manufacturing machine adjust the parameters for controlling the manufacturing machine and correct the manufacturing machine on the basis of their experiences.
In a manufacturing process for manufacturing thin-film transistor wafer for liquid crystal displays, short circuit defects are detected by using a short circuit inspecting instrument, such as disclosed in Japanese Patent Laid-open (Kokai) No. 4-72552, the short circuit defects are confirmed visually, and the short circuit defects are classified by causes including particles, aluminum residues and through holes.
The foregoing prior art designed for the automation of inspection or the automation of inspection and repair for a system for controlling manufacturing processes on the basis of the results of automatic inspection and repair of products has the following problems. The prior art automatic inspection system consists of a detecting system for detecting defects in the product, and an information processing system for analyzing information provided by the detecting system to see whether or not the product has defects and to classify defects by category. Therefore, when the quality of the product varies according to the variation of the manufacturing process within an allowable range and the automatic inspection system decides that the product is defective, the automatic inspection system needs readjustment.
Since the detection system and the information processing system are the inherent components of the automatic inspection system as mentioned above, it is difficult to alter the detection system and the information processing system substantially. Accordingly, the sensitivity of the like of the detecting system or parameters for controlling the information processing system is changed for the readjustment of the automatic inspection system. In most cases, the readjustment of the automatic inspection system to adjust the inspection criteria of the automatic inspection system to inspecting standards used in the manufacturing process is carried out by a trial-and-error method at the site of manufacture, which takes much time to make the automatic inspection apparatus function normally. If the automatic inspection system is an in-line inspecting apparatus, the operation of the associated production line must be suspended during the adjustment of the automatic inspection system.
Another automatic inspection system inspects a product to see whether or not the product is defective and, if the product has a defect, provides only information about the position of the defect in the product. When this automatic inspection system is used, defects must be classified by the operator, and it is possible to examine the parameters of the automatic inspection system to see if the parameters are proper only after the classification and analysis of the defects by the operator. Therefore, the automatic inspection system not only needs much time before the same starts normally functioning, the inspection system has the possibility of inspecting products according to inappropriate inspecting standards while the defects are being classified and analyzed.
Accordingly, if the automatic inspection system is not adjusted properly, products are inspected and repaired erroneously.
In the prior art automatic inspection system, nothing is considered about means for making the operator make a decision about whether or not correction is necessary, i.e., whether or not the defects are classified correctly, to control a correcting operation and for feeding back information about the results of examination of the results of defect classification made by the automatic inspection system by the operator to the automatic inspection system.
Similarly, when defect detection information provided by the automatic inspection system in an imperfectly adjusted condition is used as means for adjusting the manufacturing machine for manufacturing the products, it is impossible to adjust the parameters for controlling the operating condition of the manufacturing machine for properly manufacturing the products. Since correcting information produced on the basis of the results of inspection provided by the automatic inspection system is fed back to the automatic inspection system, the complete readjustment of the automatic inspection system takes much time.
Furthermore, although accurate information about defects in products and information about the working condition of a manufacturing process are necessary for securing the stability of the manufacturing process, it requires much time to examine the correlation between the manufacture of defective products and the condition of the manufacturing process, because the accurate analysis of defects and the readjustment of the manufacturing process are carried out simultaneously when the products are inspected by the aforesaid prior art automatic inspection system.
Still further, since the prior art automatic inspection system does not attach the results of inspection and the bases of the results of inspection to the inspected product, it is impossible to find which manufacturing process is causative of the defect or the causal relationship between a defect detected at the final stage of manufacture and a defect detected at the middle stage of manufacture is unknown even if the defect is detected by inspection in the next process or by final inspection.
It is an object of the present invention to provide an adjusting means capable of properly and quickly adjusting inspecting standards on the basis of which an automatic inspection system functions, in cooperation with the operator to thereby provide a method of manufacturing a semiconductor device or the like, capable of enabling automatic inspection and automatic repair, a manufacturing system for carrying out the method, an inspection method, and an inspection system for carrying out the inspection method.
With the foregoing object in view, the present invention provides the following means.
(A) An inspection system in a first aspect of the present invention comprises: an automatic inspection unit for inspecting a product according to predetermined inspecting standards and extracting defects in the product; a defect classifying and feature extracting unit for receiving information about the extracted defects provided by the automatic inspection unit, classifying the defects by category, providing the results of classification of the defects and extracting the feature data of the defects on the basis of the results of classification; and a feature data converting unit for converting the feature data into corresponding inspecting standards for the automatic inspection unit and feeding back inspecting standards obtained by conversion to the automatic inspection unit.
(B) An inspection system in a second aspect of the present invention comprises; an automatic inspection unit for inspecting a product according to predetermined inspecting standards and extracting defects in the product; a defect classifying and feature extracting unit for receiving information about the extracted defects provided by the automatic inspection unit, classifying the defects by category, providing the results of classification of the defects and extracting the feature data of the defects on the basis of the results of classification; and a feature-parameter conversion unit for converting the feature data into parameters for controlling the condition of the manufacturing machine manufacturing the product, and feeding back the parameters obtained by conversion to the manufacturing machine to adjust the manufacturing machine.
(C) The defect classifying and feature extracting unit stated in (A) or (B) is provided with a teaching means capable of teaching a correct result of defect classification when the result of defect classification provided by the defect classifying and feature extracting unit is incorrect.
(D) The inspecting system stated in (A) or (B) is provided with an information showing means capable of visually showing the result of defect classification provided by the defect classifying and feature extracting unit to the operator to enable the operator recognize the result of defect classification and information relating thereto, and to change the information or add new information to the information.
(E) The inspecting system includes an information storage means for storing the information mentioned in (D) and information about each defect.
(F) The inspection system is capable of extracting the feature data of defects from a plurality of pieces of the information mentioned in (D) and stored in the information storage means mentioned in (E) and information about the defects in the product corresponding to the information mentioned in (D), the feature data is given to the feature data converting unit mentioned in (A), and amends the inspecting standards to be used by the automatic inspection unit mentioned in (A).
(G) The inspection system is capable of extracting the feature data of defects from a plurality of pieces of the information mentioned in (D) stored in the information storage means mentioned in (E) and the information about the defects in the product, gives the feature data to the feature-parameter conversion unit mentioned in (B) and adjusts the manufacturing machine mentioned in (B).
(H) The inspection system is capable of adding information about the manufacturing process in a condition where the defects have just developed to the information mentioned in (D) stored in the information storage means mentioned in (E) and the information about the defects in the product corresponding to the information mentioned in (D), and holding and presenting the condition of the manufacturing process and historical information about the mode of development of defects in connection with each other.
(I) The inspection system includes a teaching means capable of showing the information about the defects and the related information including information about the category of an unknown defect when the defect classifying and feature extracting unit mentioned in (A) or (B) is unable to classify the results of classification of defects in the product into existing categories, and of enabling the operator to assign a new or an existing category, a name and the like to the defect of an unknown category.
(J) The information about the defect mentioned in (E), (F), (G), (H) and (I) is an image information about the defect and a region surrounding the defect.
(K) The product inspected by the automatic inspection unit (1) stated in (A) is sent to a product repair unit according to the result of defect classification provided by the defect classifying and feature extracting unit mentioned in (A) or (B), and the product is subjected to a predetermined repairing work.
(L) The product repairing operation of the product repair unit mentioned in (K) can be controlled by the operator, and the product repair unit is capable of teaching a correct result of defect classification when the result of defect classification provided by the defect classifying and feature extracting unit mentioned in (A) or (B) is incorrect and of feeding back the information about the correct result of defect classification to the defect classifying and feature extracting unit.
(M) Pattern information about an image of a detected defect is used as the attribute of the defect mentioned in (A) or (B).
(N) Signal information about the information about the detected defect is used as the attribute of the defect mentioned in (A) or (B).
(O) Information about either the result of inspection of the product or the result of measurement of the product, or both the result of inspection of the product and the result of measurement of the product is attached to the product.
(P) A manufacturing machine presumably causative of the defect is selected in view of the result of deflect classification provided by the defect classifying and feature extracting unit mentioned in (B) and the attribute of the defect, and the feature data of the defect extracted by the defect classifying and feature extracting unit mentioned in (B) is sent to the feature-parameter conversion unit mentioned in (B).
Naturally, the inspection system is independent of the foregoing automatic inspection unit. However, the automatic inspection unit may be a unit provided with a monitoring apparatus for monitoring the condition of a product, capable of inspection or monitoring and incorporated into a manufacturing machine.
The operation of the foregoing means to achieve the object of the invention will be explained hereinafter with reference to FIG. 1.
A thick line 12 represents the flow of a product in a manufacturing process. An automatic inspection unit 1 inspects a product and extracts defects according to predetermined inspecting standards. A defect classifying and feature extracting unit 2 classifies defects and extracts the feature data of the defects.
The automatic inspection unit 1 gives defect information about the defects detected through inspection to the defect classifying and feature extracting unit 2. The defect information includes images of the defects, electric signals generated upon the detection, information on the basis of which the defects are identified, and the like. The defect classifying and feature extracting unit 2 classifies the defects on the basis of the the defect information. The defects are classified on the basis of various feature data on a rule basis or a model basis. A defect classification indicating unit 6 indicates the result of defect classification to enable the correction of the result of defect classification.
The defect classification indicating unit 6 shows the result of defect classification visually to enable an operator to recognize information including the result of defect classification and the related information and to change the information or add new information thereto.
The defect classifying and feature extracting unit 2 changes the interpretation of the feature data of the corresponding defect on the basis of the result of defect classification taught thereto by the defect classification indicating unit 6.
A feature data converting unit 3 is capable of converting the feature data of the defects classified by the defect classifying and feature extracting unit 2 into inspecting standards. The feature data converting unit 3 sends the inspecting standard obtained by converting the feature data to the automatic inspection unit 1. If the result of defect classification provided by the defect classifying and feature extracting unit 2 and the result of a decision made by the automatic inspection unit 1 are different from each other, the result of defect classification provided by the defect classifying and feature extracting unit 2 is reflected through the feature data converting unit 3 on the automatic inspection unit 1.
A feature-parameter conversion unit 4 is capable of converting the feature data of the defects classified by the defect classifying and feature extracting unit 2 into control parameters relating to manufacturing conditions for a product manufacturing machine 8 for manufacturing the product. The feature-parameter conversion unit 4 gives the control parameters obtained by converting the feature data to the product manufacturing machine 8. The defect classifying and feature extracting unit 2 is capable of selecting the product manufacturing machines 8 to be readjusted on the basis of the result of defect classification and of sending information to the feature-parameter conversion units 4 connected to the selected product manufacturing machines 8.
An information storage unit 7 connected to the defect classifying and feature extracting unit 2 stores all or part of defect information about each of the defects in the product received from the automatic inspection unit 1, the result of defect classification received from the defect classifying and feature extracting unit 2, information used for defect classification, and, when the defect classifying and feature extracting unit 2 is provided with a means for obtaining image information or electric signals, image information or electric signals about defects in the product, regions surrounding the defects or other portions characterizing the defects, which are different from the information obtained by the automatic inspection unit 1.
The defect classifying and feature extracting unit 2 is capable of receiving information about the operating condition of the product manufacturing machines 8. The information received by the defect classifying and feature extracting unit 2 is stored in addition to the information about the product in the information storage unit 7. The information about the defects and the like stored in the information storage unit 7 is subjected to statistical data processing when necessary and the statistically processed information is shown to the operator by the defect classification indicating unit 6 connected to the defect classifying and feature extracting unit 2. All or part of the information about each of the defects stored in the information storage unit 7 and the information provided by the defect classifying and feature extracting unit 2 are sent to a process control system 5.
A product sorting unit 9 selects defective products which are to be repaired and delivers the selected defective products onto a repair line 13 to send the defective products to relevant repair units 11 according to instructions given thereto from the defect classifying and feature extracting unit 2.
The repair units 11 may be substituted by a single repair unit capable of removing all kinds of defects or each of the repair units 11 may be capable of removing a specific defect. Although the repair units 11 are capable of automatic repairing operation, they enable the operator to determine whether or not repair is necessary, and, when the category of the defect is different from that determined by the defect classifying and feature extracting unit 2, they are capable of informing the defect classifying and feature extracting unit 2 to that effect.
An information attaching unit 14 attaches information about the result of inspection of the product by the automatic inspection unit 1 and the associated information to the product.
With the inspection system thus constructed efficient inspection of products is made possible for manufacturing products with high reliability according to the manufacturing process.
The present invention has the following advantages.
(A) Since the inspecting standards by which the automatic inspection unit inspects products can be automatically readjusted by the defect classifying and feature extracting unit 2 of FIG. 1 or can be semiautomatically readjusted through the feature data converting unit 3 of FIG. 1 under operator""s supervision using the defect classification indicating unit 6 connected to the defect classifying and feature extracting unit 2, the inspecting standards can be readjusted to inspecting standards conforming to the process conditions without stopping the automatic inspection unit.
(B) Since the inspecting standards can be automatically readjusted by the defect classifying and feature extracting unit 2 of FIG. 1 or can be semiautomatically readjusted through the feature data comparing unit 3 of FIG. 1 under operator""s supervision using the defect classification indicating unit 6 connected to the defect classifying and feature extracting unit 2, the inspecting reliability of the automatic inspection unit can be improved quickly.
(C) The effect mentioned in (A) curtails the time necessary for starting up the automatic inspection unit when products of one kind being inspected are changed for those of another kind.
(D) Since the effect mentioned in (A) curtails the time necessary for adjusting the automatic inspection unit, the number of products which are inspected on the basis of inappropriate inspecting standards can be reduced.
(E) Since the classification of defects by the defect classifying and feature extracting unit 2 of FIG. 1 enables the categories of defects to be known and thereby the manufacturing machines presumably causative of the defects can be determined. The manufacturing process can be stabilized quickly by adjusting the manufacturing machines taking into consideration the characteristic defects of the manufacturing machines through the operation of the feature-parameter conversion unit 4 of FIG. 1.
(F) The effect mentioned in (B) enables correct instructions to be given to the repairing process, so that the incorrect repair of products can be prevented.
(G) The defect classifying and feature extracting unit 2 of FIG. 1 is adjusted while defects are removed by operating a defect classification input unit 10 connected to the repair unit 11 of FIG. 1 and, consequently, the inspecting standards by which the automatic inspection unit inspects products can be readjusted.
(H) The defect classification indicating unit 6 processes the information stored in the information storage unit 7 of FIG. 1 and indicates the processed information to enable the operator to grasp easily the relation between the causes of defects and the condition of the manufacturing process.
(I) Information given to the information storage unit 7 of FIG. 1 is transferred to the process control system 5 of FIG. 1 to enable the control of the condition of the entire manufacturing process.
(J) When the result of defect classification provided by the defect classifying and feature extracting units 2 of the automatic inspection units installed respectively at different positions in the manufacturing process and the feature data of defects are compared and when the result of defect classification provided by the defect classifying and feature extracting units 2 are similar to each other, a portion of the manufacturing process between the automatic inspection units connected to those defect classifying and feature extracting units 2 need not be monitored and hence either of the upstream and downstream automatic inspection units of the manufacturing process may be omitted. The automatic inspection units can thus be installed at optimum positions in the manufacturing process.
(K) Since the information attaching unit 14 of FIG. 1 attaches the result of inspection and the associated information to the inspected product, the manufacturing processes causative of the defects and the causal relation between defects detected by inspection at the final stage and those detected at the middle stage can be known by comparing the information attached to the product and the result of inspection in the following manufacturing processes or the result of final inspection.